Year	Percent
1960-01-01	9.248830000000000
1961-01-01	8.817800000000000
1962-01-01	7.780069999999999
1963-01-01	6.592389999999999
1964-01-01	7.991010000000000
1965-01-01	10.522100000000000
1966-01-01	10.209000000000000
1967-01-01	10.294300000000000
1968-01-01	10.690400000000000
1969-01-01	13.211100000000000
1970-01-01	13.803400000000000
1971-01-01	14.058700000000000
1972-01-01	13.765900000000000
1973-01-01	13.993000000000000
1974-01-01	16.396700000000000
1975-01-01	16.962500000000000
1976-01-01	17.831500000000000
1977-01-01	22.900100000000000
1978-01-01	24.187800000000000
1979-01-01	21.901600000000000
1980-01-01	18.261400000000000
1981-01-01	17.728500000000000
1982-01-01	17.901600000000000
1983-01-01	17.837900000000000
1984-01-01	17.075800000000000
1985-01-01	18.668900000000000
1986-01-01	20.327700000000000
1987-01-01	21.013100000000000
1988-01-01	21.174800000000000
1989-01-01	20.264000000000000
1990-01-01	20.058400000000000
1991-01-01	19.638700000000000
1992-01-01	20.156700000000000
1993-01-01	18.264100000000000
1994-01-01	15.849300000000000
1995-01-01	16.890100000000000
1996-01-01	16.114900000000000
1997-01-01	15.097100000000000
1998-01-01	14.311300000000000
1999-01-01	13.986100000000000
2000-01-01	13.762200000000000
2001-01-01	12.622500000000000
2002-01-01	13.038600000000000
2003-01-01	13.659800000000000
2004-01-01	13.958700000000000
2005-01-01	14.352300000000000
2006-01-01	15.020600000000000
2007-01-01	16.654100000000000
2008-01-01	17.198400000000000
2009-01-01	17.569900000000000
2010-01-01	18.724800000000000
2011-01-01	22.971100000000000
2012-01-01	22.784700000000000
2013-01-01	22.464400000000000
2014-01-01	23.180900000000000
2015-01-01	25.227800000000000
2016-01-01	25.930300000000000